Ultrasonic imaging is widely used to monitor fetal growth and development during the first and second trimester and multiple studies document the resultant positive impacts on fetal and maternal outcomes. However, current methods fail to provide adequate visualization of key structures in many patients and alternative imaging modes are rarely available to these patients. We have developed novel ultrasonic beamforming methods that, instead of imaging echo brightness, display the spatial coherence of backscattered echoes. These methods, in simulation, phantom, and initial clinical studies, show markedly improved image quality over conventional ultrasonic images, especially in difficult-to-image patients. We propose to construct a real-time coherence imaging system on a commercially available diagnostic scanner. We propose phantom and simulation studies to assess and optimize coherence-based imaging methods under a wide range of imaging conditions. Related studies will examine the application of frequency and spatial compounding, synthetic aperture imaging, and adaptive imaging methods to coherence beamforming. Clinical studies are proposed to assess the role of coherence imaging in key fetal diagnostic tasks in first trimester and second trimester scans. Quantitative image quality metrics and observer studies are proposed to compare B-mode and coherence images with an emphasis on difficult-to-image patients. Related studies will measure the contribution of various sources of image degradation in fetal scans and compare image artifacts observed in conventional and coherence-based ultrasonic images. If successful, the proposed research could lead to a new class of ultrasonic beamforming methods that operate in imaging environments in which current methods fail.